Introduction to C++ find()
C++ find() function is part of the standard library function which tries to find the first occurrence of the specified range of element where the range starts with first range to last range and that iterator encounters the first element, compares for the value which must be equal after all possible comparisons and if no element is found it returns the last element. For making all the comparisons it makes use of the operator = for comparison. If find() function performs any unnecessary action it throws exceptions that are not required by the programmer.
Syntax:
Syntax flow is in a way where the template is having the class InputIterator with the range of first, last and iterator for value comparison.
template <class InputIterator, class T>
InputIteratorfind (InputIteratorfrst, Input_Iteratorlst, const T&vl);find() function searches for the value which the iterator points to and then the template comprising of class InputIterator.
- frst: It is the argument that ranges from first of the iterator to the last of the iterator consisting of all the possible elements between first and last including the elements with specific range and criteria.
- lst: It is the argument that represents the last argument in the entire specified range and then compares the value one by one which is pointed by the iterator of the range.
- vl: The value pointed by the iterator is searched and considered for further usage.
- If in case an iterator to the first element within the range is not the same after comparing with the existing value, then the function returns the last value after all searches and comparisons performed.
How find() Function Works in C++?
Unlike other function find() function works in a way where the find() function template have some components and arguments which they try to work for with the fact that the template specifies some ranges with first and last of the elements. Elements lie in the range make traversals and then let the iterator pointing to the value to return some values. If the value after comparison does not comes out to be equal or the same, then it will return the last element as the value for consideration otherwise it will return the first value always at the time of consideration. The input of iterators occurs with the first and last of the elements in sequence otherwise the range is searched first or last consisting of all the elements pointed by first or last of the iterators. It makes use of the = operator for any functional manipulation or changes while finding the first occurrence of the element. If the element pointed by the iterator with the specified range is found, then it will return the first element of the entire range of elements otherwise it will return the last element. Even in case that find() function is not able to search the first element in the range then it will return the last element. It throws an exception if some unwanted actions are performed while element comparisons or some invalid arguments are passed then It leads to exceptions. The time complexity for this function comes out to be linear.
Examples to Implement C++ find() Function
Below are the examples of C++ find():
Example #1
This program illustrates the std C++ find() function with a specified range including beginning and ending of the function as shown in the output.
Code:
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main(void) {
intvl = 3;
vector<int>vc = {8, 9, 3, 2, 4};
auto rslt = find(vc.begin(), vc.end(), vl);
if (rslt != end(vc))
cout<< "Elements_present_in_Vector " <<vl<<endl;
vl = 18;
rslt = find(vc.begin(), vc.end(), vl);
if (rslt == end(vc))
cout<<"Element_not_present_in_Vector" <<vl<<endl;
return 0;
}Output:
Example #2
This program demonstrates the C++ find() function which is used to search the element from the actual vector using iterator for the traversal of start and end of the function by comparing all the elements and then initializing a value with some value to verify as shown in the output.
Code:
#include <iostream>
#include <vector>
#include <algorithm>
int main ()
{
std::vector<int>vc_tr { 20, 10, 15, 12 };
std::vector<int>::iterator tr;
std::cout<< "Actual_Vector:";
for (int j=0; j<vc_tr.size(); j++)
std::cout<< " " <<vc_tr[j];
std::cout<< "\n";
intsrch = 25;
tr = std::find (vc_tr.begin(), vc_tr.end(), srch);
if (tr != vc_tr.end())
{
std::cout<< "All_Elements " <<srch<<" found_at : " ;
std::cout<<tr - vc_tr.begin() << " (Started_from_1st_index) \n" ;
}
else
std::cout<< "srch_Not_Found_Element.\n\n";
return 0;
}Output:
Advantages of C++ find()
- find() function as part of the standard library can be used by the programmers for searching elements at the time of comparison with the first and last element within a specified range.
- The iterator pointing to the first or the last element can enhance or manipulate the entire traversal process as all the elements present are with the index were retrieving the value is important for comparisons and other operations.
- It enhances the reusability of the code base as it not important to design and define a function again and again wherever required we can call the find function and the task becomes simplified as it will be already present within the standard library.
- Testing of individual functions becomes easy as the scope for re-writing function becomes simplified.
- The division of the program makes the view of the codebase clear and understandable by the programmers to write a new and enhanced form of code.
Conclusion
find() function in C++ is a function that is part of the standard library function and helps to retrieve elements to search desired elements within a specified range which resolve the complexity of reusability for programmers to get a view for managing the code and iterator usage.
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